## Why
The PID-managed daemon updater downloaded the standalone installer directly,
bypassing Codex's configured outbound proxy policy.
## What changed
- Build the updater's HTTP client from the effective Codex configuration so
`features.respect_system_proxy` also applies to installer downloads.
- Use the route-aware client pool for the installer request.
- Warn and fall back to the default `reqwest` proxy behavior when configuration
cannot be loaded, allowing updates to continue.
## Testing
Added tests for proxy-policy selection, configuration-load fallback, exact
installer URL usage, byte preservation, and non-success HTTP responses.
GitOrigin-RevId: 559668eb40314d43afa6512da66e59e32cc1b93c
99eb575649